# input
X = int(input())

# step1
if X >= 30:
    switch = "Yes"
else:
    switch = "No"

# output
print(switch) X = int(input()) X int(input()) int input() input if X >= 30:
    switch = "Yes"
else:
    switch = "No"

# output X >= 30 X 30 switch = "Yes" switch "Yes" switch = "No" switch "No" print(switch) print switch switch = "No" "No" switch X = int(input()) int(input()) X switch = "Yes" "Yes" switch
# input
X = int(input())

# step1
if X >= 30:
    switch = "Yes"
else:
    switch = "No"

# output
print(switch)